1. Field of the Invention
The present invention relates to the improvements of an air-cleaning apparatus or air cleaner.
2. Discussion of the Prior Art
There is known an air cleaner for a motor vehicle, which is assembled using two housings together with a filter element to be accommodated in the housings. One example of this type of air cleaner is disclosed in Laid-Open Publication No. 4-79958 of Unexamined Japanese Utility Model Application. The prior air cleaner includes: (a) a first housing having an air inlet and a first opening; (b) a second housing having a second opening, a sealing surface surrounding the second opening, and an air outlet; (c) a filter element having a sealing member which is attached to the outer periphery of the filter element and which is interposed between the first and second housings when the two housings are assembled together. The first housing has (d) a first engaging portion located outwardly of the first opening. The second housing has (e) a second engaging portion which is located outwardly of the sealing surface and which is engageable with the first engaging portion when the two engaging portions are displaced relative to each other in a direction substantially parallel to the plane in which the sealing member extends. The second engaging portion defines the distance between the first and second housings assembled together, as measured in a direction substantially perpendicular to the plane of the first opening. The air cleaner further includes (f) a clamp device for clamping corresponding portions of the first and second housings remote from the first and second engaging portions, so that the two housings are secured to each other. The clamp device cooperates with the first and second engaging portions engaged with each other, to cause the sealing surface of the second housing to come into sealing contact with the sealing member accommodated in the first housing.
Thus, the above-described air cleaner is assembled by engaging the first and second engaging portions with each other on one of opposite side surfaces of the air cleaner and clamping the first and second housings together on the other side surface with the clamp device. In this arrangement, it is not necessary to provide another clamp device on the above-indicated one side surface, since the first and second housings are connected to each other by the engagement of the first and second engaging portions. Thus, the prior air cleaner may be manufactured at lower cost as compared with an air cleaner wherein a first and a second housing are assembled together by using a clamp device on each of opposite side surfaces of the air cleaner. Moreover, the prior arrangement facilitates opening and closing of the first and second housings, thereby making it easier to clean or replace the filter element accommodated therein.
In the above air cleaner, the sealing surface of the second housing is held in sealing contact with the sealing member attached to the filter element, for the purpose of preventing dust from being mixed with air flowing through the air cleaner. To this end, however, it is not essential to interpose the sealing member between the first and second housings as taught by the above-identified document, but it is possible that the first housing support the sealing member by limiting the depth of occupation of the sealing member into the first housing. In the latter case, it is also required that the sealing surface of the second housing be held in sealing contact with the sealing member of the filter element when the second housing closes the first housing.
FIG. 21 shows a manner in which the above air cleaner is assembled. Specifically described, a worker moves a second housing 206 relative to a first housing 202 in a direction indicated at an arrow, so that a second engaging portion 200 of the second housing 206 is displaced in a rightward direction in FIG. 21 so as to engage a first engaging portion 204 of the first housing 202. Since the second housing 206 is displaced in a direction from inside, toward outside, of the first housing 202, an outer edge 210 of a sealing surface 208 of the second housing 206 may interfere with a sealing member 212 accommodated in the first housing 202 and may even peel the sealing member 212 off the filter element, thereby causing elastic deformation of the sealing member 212 as illustrated in the figure. Thus, the prior air cleaner is not assured of satisfactory air-tight sealing between the first and second housings 202, 206, due to the elastic deformation of the sealing member 212 that remains after the two housings 202, 206 are assembled together.